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Scientific Reports Jun 2024Biological invasions threaten global biodiversity, altering landscapes, ecosystems, and mutualistic relationships like pollination. Orchids are one of the most...
Biological invasions threaten global biodiversity, altering landscapes, ecosystems, and mutualistic relationships like pollination. Orchids are one of the most threatened plant families, yet the impact of invasive bees on their reproduction remains poorly understood. We conduct a global literature survey on the incidence of invasive honeybees (Apis mellifera) on orchid pollination, followed by a study case on Australian orchids. Our literature survey shows that Apis mellifera is the primary alien bee visiting orchids worldwide. However, in most cases, introduced honeybees do not deposit orchid pollen. We also test the extent to which introduced honeybees affect orchid pollination using Diuris brumalis and D. magnifica. Diuris brumalis shows higher fruit set and pollination in habitats with both native and invasive bees compared to habitats with only introduced bees. Male and female reproductive success in D. magnifica increases with native bee abundance, while conversely pollinator efficiency decreases with honeybee abundance and rises with habitat size. Our results suggest that introduced honeybees are likely involved in pollen removal but do not effectively deposit orchid pollen, acting as pollen wasters. However, Apis mellifera may still contribute to pollination of Diuris where native bees no longer exist. Given the global occurrence of introduced honeybees, we warn that certain orchids may suffer from pollen depletion by these invaders, especially in altered habitats with compromised pollination communities.
Topics: Animals; Bees; Pollination; Orchidaceae; Pollen; Introduced Species; Ecosystem; Male; Reproduction; Australia; Female
PubMed: 38890342
DOI: 10.1038/s41598-024-64218-x -
Nature Communications Jun 2024Although different ecological factors shape adaptative evolution in natural habitats, we know little about how their interactions impact local adaptation. Here we used...
Although different ecological factors shape adaptative evolution in natural habitats, we know little about how their interactions impact local adaptation. Here we used eight generations of experimental evolution with outcrossing Brassica rapa plants as a model system, in eight treatment groups that varied in soil type, herbivory (with/without aphids), and pollination mode (hand- or bumblebee-pollination), to study how biotic interactions affect local adaptation to soil. First, we show that several plant traits evolved in response to biotic interactions in a soil-specific way. Second, using a reciprocal transplant experiment, we demonstrate that significant local adaptation to soil-type evolved in the "number of open flowers", a trait used as a fitness proxy, but only in plants that evolved with herbivory and bee pollination. Whole genome re-sequencing of experimental lines revealed that biotic interactions caused a 10-fold increase in the number of SNPs across the genome with significant allele frequency change, and that alleles with opposite allele frequency change in different soil types (antagonistic pleiotropy) were most common in plants with an evolutionary history of herbivory and bee pollination. Our results demonstrate that the interaction with mutualists and antagonists can facilitate local adaptation to soil type through antagonistic pleiotropy.
Topics: Pollination; Soil; Animals; Herbivory; Brassica rapa; Bees; Adaptation, Physiological; Polymorphism, Single Nucleotide; Biological Evolution; Flowers; Gene Frequency; Aphids; Ecosystem
PubMed: 38890322
DOI: 10.1038/s41467-024-49383-x -
Proceedings. Biological Sciences Jun 2024Extreme heat poses a major threat to plants and pollinators, yet the indirect consequences of heat stress are not well understood, particularly for native solitary bees....
Extreme heat poses a major threat to plants and pollinators, yet the indirect consequences of heat stress are not well understood, particularly for native solitary bees. To determine how brief exposure of extreme heat to flowering plants affects bee behaviour, fecundity, development and survival we conducted a no-choice field cage experiment in which were provided blueberry (), phacelia () and white clover () that had been previously exposed to either extreme heat (37.5°C) or normal temperatures (25°C) for 4 h during early bloom. Despite a similar number of open flowers and floral visitation frequency between the two treatments, female bees provided with heat-stressed plants laid approximately 70% fewer eggs than females provided with non-stressed plants. Their progeny received similar quantities of pollen provisions between the two treatments, yet larvae consuming pollen from heat-stressed plants had significantly lower survival as larvae and adults. We also observed trends for delayed emergence and reduced adult longevity when larvae consumed heat-stressed pollen. This study is the first to document how short, field-realistic bursts of extreme heat exposure to flowering host plants can indirectly affect bee pollinators and their offspring, with important implications for crop pollination and native bee populations.
Topics: Animals; Bees; Fertility; Pollination; Female; Extreme Heat; Hot Temperature; Longevity; Pollen
PubMed: 38889783
DOI: 10.1098/rspb.2024.0714 -
Biology Letters Jun 2024Floral longevity, the length of time a flower remains open and functional, is a phylogenetically conserved trait that balances floral costs against the rate at which...
Floral longevity, the length of time a flower remains open and functional, is a phylogenetically conserved trait that balances floral costs against the rate at which flowers are pollinated. Floral symmetry has long been considered a key trait in floral evolution. Although zygomorphic (bilaterally symmetric) flowers typically receive fewer floral visitors than actinomorphic (radially symmetric) flowers, it is yet to be determined whether this could be associated with longer floral longevity. Using newly collected field data combined with data from the literature on 1452 species in 168 families, we assess whether floral longevity covaries with floral symmetry in a phylogenetic framework. We find that zygomorphic flowers last on average 1.1 days longer than actinomorphic flowers, a 26.5% increase in longevity, with considerable variation across both groups. Our results provide a basis to discuss the ecological and evolutionary costs of zygomorphy for plants. Despite these costs, zygomorphy has evolved numerous times throughout angiosperm history, and we discuss which rewards may outweigh the costs of slower pollination in zygomorphic flowers.
Topics: Flowers; Biological Evolution; Pollination; Magnoliopsida; Phylogeny
PubMed: 38889773
DOI: 10.1098/rsbl.2024.0082 -
BMC Plant Biology Jun 2024Wheat grain development in the first few days after pollination determines the number of endosperm cells that influence grain yield potential and is susceptible to...
BACKGROUND
Wheat grain development in the first few days after pollination determines the number of endosperm cells that influence grain yield potential and is susceptible to various environmental conditions, including high night temperatures (HNTs). Flag leaves and seed-associated bracts (glumes, awn, palea, and lemma) provide nutrients to the developing seed. However, the specific metabolic roles of these tissues are uncertain, especially their dynamics at different developmental stages and the time in a day. Tissue- and time-dependent metabolite profiling may hint at the metabolic roles of tissues and the mechanisms of how HNTs affect daytime metabolic status in early grain development.
RESULTS
The metabolite profiles of flag leaf, bract, seed (embryo and endosperm), and entire spike were analyzed at 12:00 (day) and 23:00 (night) on 2, 4, and 6 days after fertilization under control and HNT conditions. The metabolite levels in flag leaves and bracts showed day/night oscillations, while their behaviors were distinct between the tissues. Some metabolites, such as sucrose, cellobiose, and succinic acid, showed contrasting oscillations in the two photosynthetic tissues. In contrast, seed metabolite levels differed due to the days after fertilization rather than the time in a day. The seed metabolite profile altered earlier in the HNT than in the control condition, likely associated with accelerated grain development caused by HNT. HNT also disrupted the day/night oscillation of sugar accumulation in flag leaves and bracts.
CONCLUSIONS
These results highlight distinct metabolic roles of flag leaves and bracts during wheat early seed development. The seed metabolite levels are related to the developmental stages. The early metabolic events in the seeds and the disruption of the day/night metabolic cycle in photosynthetic tissues may partly explain the adverse effects of HNT on grain yield.
Topics: Triticum; Seeds; Plant Leaves; Edible Grain; Metabolome; Temperature; Photosynthesis; Time Factors
PubMed: 38886651
DOI: 10.1186/s12870-024-05190-6 -
Ecology and Evolution Jun 2024We investigated the plant-pollinator interactions of the Mexican grass-carrying wasp native to North America and introduced in Europe in the 1960sthrough the use of...
We investigated the plant-pollinator interactions of the Mexican grass-carrying wasp native to North America and introduced in Europe in the 1960sthrough the use of secondary data from citizen science observations. We applied a novel data exchange workflow from two global citizen science platforms, iNaturalist and Pl@ntNet. Images from iNaturalist of the wasp were used to query the Pl@ntNet application to identify possible plant species present in the pictures. Simultaneously, botanists manually identified the plants at family, genus and species levels and additionally documented flower color and biotic interactions. The goals were to calibrate Pl@ntNet's accuracy in relation to this workflow, update the list of plant species that visits as well as its flower color preferences in its native and introduced ranges. In addition, we investigated the types and corresponding frequencies of other biotic interactions incidentally captured on the citizen scientists' images. Although the list of known host plants could be expanded, identifying the flora from images that predominantly show an insect proved difficult for both experts and the Pl@ntNet app. The workflow performs with a 75% probability of correct identification of the plant at the species level from a score of 0.8, and with over 90% chance of correct family and genus identification from a score of 0.5. Although the number of images above these scores may be limited due to the flower parts present on the pictures, our approach can help to get an overview into species interactions and generate more specific research questions. It could be used as a triaging method to select images for further investigation. Additionally, the manual analysis of the images has shown that the information they contain offers great potential for learning more about the ecology of an introduced species in its new range.
PubMed: 38882531
DOI: 10.1002/ece3.11537 -
PNAS Nexus Jun 2024The discourse surrounding the structural organization of mutualistic interactions mostly revolves around modularity and nestedness. The former is known to enhance the...
The discourse surrounding the structural organization of mutualistic interactions mostly revolves around modularity and nestedness. The former is known to enhance the stability of communities, while the latter is related to their feasibility, albeit compromising the stability. However, it has recently been shown that the joint emergence of these structures poses challenges that can eventually lead to limitations in the dynamic properties of mutualistic communities. We hypothesize that considering compound arrangements-modules with internal nested organization-can offer valuable insights in this debate. We analyze the temporal structural dynamics of 20 plant-pollinator interaction networks and observe large structural variability throughout the year. Compound structures are particularly prevalent during the peak of the pollination season, often coexisting with nested and modular arrangements in varying degrees. Motivated by these empirical findings, we synthetically investigate the dynamics of the structural patterns across two control parameters-community size and connectance levels-mimicking the progression of the pollination season. Our analysis reveals contrasting impacts on the stability and feasibility of these mutualistic communities. We characterize the consistent relationship between network structure and stability, which follows a monotonic pattern. But, in terms of feasibility, we observe nonlinear relationships. Compound structures exhibit a favorable balance between stability and feasibility, particularly in mid-sized ecological communities, suggesting they may effectively navigate the simultaneous requirements of stability and feasibility. These findings may indicate that the assembly process of mutualistic communities is driven by a delicate balance among multiple properties, rather than the dominance of a single one.
PubMed: 38881844
DOI: 10.1093/pnasnexus/pgae209 -
Scientific Reports Jun 2024Floral nectar sugar composition is assumed to reflect the nutritional demands and foraging behaviour of pollinators, but the relative contributions of evolutionary and...
Floral nectar sugar composition is assumed to reflect the nutritional demands and foraging behaviour of pollinators, but the relative contributions of evolutionary and abiotic factors to nectar sugar composition remain largely unknown across the angiosperms. We compiled a comprehensive dataset on nectar sugar composition for 414 insect-pollinated plant species across central Europe, along with phylogeny, paleoclimate, flower morphology, and pollinator dietary demands, to disentangle their relative effects. We found that phylogeny was strongly related with nectar sucrose content, which increased with the phylogenetic age of plant families, but even more strongly with historic global surface temperature. Nectar sugar composition was also defined by floral morphology, though it was not related to our functional measure of pollinator dietary demands. However, specialist pollinators of current plant-pollinator networks predominantly visited plant species with sucrose-rich nectar. Our results suggest that both physiological mechanisms related to plant water balance and evolutionary effects related to paleoclimatic changes have shaped floral nectar sugar composition during the radiation and specialisation of plants and pollinators. As a consequence, the high velocity of current climate change may affect plant-pollinator interaction networks due to a conflicting combination of immediate physiological responses and phylogenetic conservatism.
Topics: Plant Nectar; Pollination; Biological Evolution; Phylogeny; Flowers; Sugars; Animals; Insecta; Sucrose; Europe; Magnoliopsida; Climate Change
PubMed: 38879632
DOI: 10.1038/s41598-024-64755-5 -
Scientific Reports Jun 2024The aim of this study was to investigate the fertility of "Huajin 6" and the effect of exogenous methyl jasmonate on its fertility. In this study, "Huajin 6", "Huajin 6"...
The aim of this study was to investigate the fertility of "Huajin 6" and the effect of exogenous methyl jasmonate on its fertility. In this study, "Huajin 6", "Huajin 6" treated with methyl jasmonate and "Damaohua" were used as the research objects, the stamen phenotypes and the shape of pollen grains were observed, pollen viability and stigma receptivity were measured. The results showed that the pistil structure and function were normal, and although the stamen anthers did not dehisce, they were still capable of producing pollen with a certain amount of vigor. Methyl jasmonate could promote the opening of the flowers of "Huajin 6" and improve the development of pollen grains to a certain extent, but it could not promote anthers dehiscence of "Huajin 6". This study can provide theoretical guidance for the cultivation of new honeysuckle varieties using "Huajin 6".
Topics: Oxylipins; Flowers; Pollen; Fertility; Cyclopentanes; Acetates; Lonicera; Pollination
PubMed: 38877134
DOI: 10.1038/s41598-024-64435-4 -
Scientific Reports Jun 2024Elevated atmospheric carbon dioxide (eCO) can affect plant growth and physiology, which can, in turn, impact herbivorous insects, including by altering pollen or plant...
Elevated atmospheric carbon dioxide (eCO) can affect plant growth and physiology, which can, in turn, impact herbivorous insects, including by altering pollen or plant tissue nutrition. Previous research suggests that eCO can reduce pollen nutrition in some species, but it is unknown whether this effect is consistent across flowering plant species. We experimentally quantified the effects of eCO across multiple flowering plant species on plant growth in 9 species and pollen chemistry (%N an estimate for protein content and nutrition in 12 species; secondary chemistry in 5 species) in greenhouses. For pollen nutrition, only buckwheat significantly responded to eCO, with %N increasing in eCO; CO treatment did not affect pollen amino acid composition but altered secondary metabolites in buckwheat and sunflower. Plant growth under eCO exhibited two trends across species: plant height was taller in 44% of species and flower number was affected for 63% of species (3 species with fewer and 2 species with more flowers). The remaining growth metrics (leaf number, above-ground biomass, flower size, and flowering initiation) showed divergent, species-specific responses, if any. Our results indicate that future eCO is unlikely to uniformly change pollen chemistry or plant growth across flowering species but may have the potential to alter ecological interactions, or have particularly important effects on specialized pollinators.
Topics: Carbon Dioxide; Pollen; Atmosphere; Species Specificity; Magnoliopsida; Flowers; Plant Development
PubMed: 38877021
DOI: 10.1038/s41598-024-63967-z